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1   /*
2    * Copyright 2002,2004 The Apache Software Foundation.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.jelly.tags.core;
17  
18  import org.apache.commons.jelly.MissingAttributeException;
19  import org.apache.commons.jelly.TagSupport;
20  import org.apache.commons.jelly.XMLOutput;
21  import org.apache.commons.jelly.expression.Expression;
22  
23  /***
24   * A tag which removes the variable of the given name from the current variable scope.
25   *
26   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
27   * @version $Revision: 155420 $
28   */
29  public class RemoveTag extends TagSupport {
30  
31      private Expression var;
32  
33      public RemoveTag() {
34      }
35  
36      // Tag interface
37      //-------------------------------------------------------------------------
38      public void doTag(XMLOutput output) throws MissingAttributeException {
39          if (var != null) {
40              context.removeVariable( var.evaluateAsString(context) );
41          }
42          else {
43              throw new MissingAttributeException("var");
44          }
45      }
46  
47      // Properties
48      //-------------------------------------------------------------------------
49  
50      /***
51       * Sets the name of the variable which will be removed by this tag..
52       */
53      public void setVar(Expression var) {
54          this.var = var;
55      }
56  }